Screen for ball mills



1931. H, s. LEE ET AL SCREEN FOR BALL MILLS V Filed Jan. 11, 1928 INVENTORJ flaw/2) Q97 BY W @67 Be r Mhi f/E 5 A7 ORNEY segments of the screen.

Patented Feb. 24, 1931 c e-Em e ejee ev tsT Application filea January 1 -ie2e. seriei 1m etasee f This invention relates to"screens-for ball mills,cement pulverizing drums or any other drums which employs tumbling work'. Howform of rotating crushing media or v ever,'it is particularly directed to the ball tube mills-fused inpreparing the raw :ma-

7 In the drawings F lis a fragmentary perspectiveview partly in sect-ionotball tube mill. f a F 1g.2 s'an elevational VlGW of one ofthe Fig. 3 is a isecltion on'the line 3-3;of Fig.2. In cement rnill's 1t s c'ustomary-to'fcrush orgrind the 'marble' or limestone and clay I I and grind thecement clinker by means' ot what is'called a ball-tube n11l'l.- Th1s is a are a load of balls, slugs, media.

abrading the screens or phragms that guard the compartment or CllVlCle from another. These screens soon wear and have to be replaced due to the constant abrading action of the-balls and the work. The openings through the screens become choked and clogged due to the peening of the metal at the edges of the openings by the action of the balls.

It is the object of the present invention to so form the openings of the screens that they are not subject to a peening action clog the openings. This is accomplished in two ways, namely, by the arrangement and disposition of the openings, the shaping or flaring of the the peening action,- it any, opening. y

a designates the revolving drumor tube of a conventional mill. However, the character of the drum may be limits as there are numerous difierent kinds of mills now on the market; it simply illustrates one form. I) is a screen or'perforated diaphragm which is somewhat concave in 1 the center s'ofathe diaphragm: This inakes the long; avayl of; the :hole :drreQtly pa-zrzallel .to terial and finishing cement in cement mill;

.-;: These, screens or plat ,fa-lling; :of} the W011i and ."the ba Y plates,i'beingeapproiiimately two r-1 ches thick -3, =the;;character t t the? press ilnptoved:segmentwil l, m in-g's ,onrthfe-sidewthrou -l 7 WW long drum or tube which isdivided into one or more compartments by means of screens or diaphragms. lVithin these T compartments or other crushing They are raisedby' the rotating drum and dropped on the material being worked" upon. They are consequently deforming and iltinS-gth-lOugh the plate arejofi th siredy in establishing; the A perforating dia fi outlet end of theone compartment -tered"-zone.

v 1 We'constructthe screens-'ofa toughJna-terial preferably a high manganese steel, butso tervenei between;

varied within wide V fairly close togeth vided on the plate.

Tth'ezusual fashionzif'cdesignates a aseginent any point of. the rrotatingwinasg andgconse quently, cuts, the abrading'j ac t1on:.do\'vn-to-i a- V mnnmu'mu:

p sarerelat velyfhefayy a to withstancl-theheavyshocks in dentf to the I -s:upon the andotten stillihibk'er :Referrise tion feldkare flared: asia andtheplate isurta ings is rounde'clioaer a ieX{0 'f-QW At .9 th

that is, at this point the" opening op ning s r-p f m Brs'sizef or iwhat escr e .7. Y opening 1/; at .n -arg zzthe prevent cloggingafter -passed; througlrthe mecapacity of the hole to the material.- has far as t lie broaderifeatures of the invention 1. are concerned we do -not;care.tozbelimited-to a partic lar kin o erably a casting. 1 which will steeL; vflhe plate-is prefi e find thegopenings constructed as above described resist successfully tion Zofg the work-and-the balls, Any peening so that does take'place-is on thecrowns that in eiop i g -i Th rafm teredfazone ofthe openings; is vremoved about ahalf an inch fromthe surface and isthefre- :tore located in the solidestimass-ofthe plate.

On the other handby flaring the-openingson practicallyka, 4t5 ,-fanglev and locating them r narrow crowns are pro- These vby reason of their dimensions aref-much easiergt'o ,distorta'than that portion of the metal acent the metered zone of the openings. 'The result is c that such peening action as does occur is'natmetered openings.

Vterior away from and therefore save-the distortion urally in the direction of the crowns and hence any distortion" of material works to wards the crown rather than down into the On the crowns'it is worn off gradually by the abrasion of the work and the material, and consequently in no way tends to clog the openings. 1

We find it desirable to stagger the openingas clearly shown in Fig. 2, -o This adds to the strength of the plate and also We findit'desirable in carrying out our plan to confine the;

to the surface of the plate peening entirely and keep it out of the openings. 7

\Ve find that the flaring-serves three functions in resisting the clogging of the metered portion of the openings: first, it avoids all sharp or weak corners which may be easily 'peened over; secondly, it removes the me tere d portion'of the opening far into the'inthe metered portions of third, it forms weakened crowns between the flared openings which are arranged first to give way in response to any peening-action into the metered openings.

' posed so that the comprising a plate I openings therethrough which are relatively We have found that plates constructed in accordance with ourfinvention' are capable of withstanding service for upwards of a year,

- whereas plates built according to the common custom ofthe trade will last only a few weeks when these will have to be repaired or replaced due to the choking of the openings by the peening action.

'By the word metered we do not wish to conveyth'e impression of technical accuracy of these metered zones but simply that this is uniformly arranged,

the peening act on; and I of the metal the opening, said opening having a metered portion connecting the oppositely converging walls, said plurality of openings being disposed so that the lengthwise dimensions substantially parallel an are having the aXis of the" mill as a center,'whereby the balls in the mill move across theopenings in a direction substantially paralleling the length of the openings to minimizethe peening act on on V the edges iof th'e opening, said openings being and relatively close to each other, to provide relatively narrow,

weakened, and uniform crowns between them,

,stantiallyparallels an arc having theaxis of "the 1n1ll asa center, whereby the balls n the mill move across the openings 1n a direction substantially parallel with the length of the openingsand contactwith the said ccnverg-,;

fing Walls to minimize the peening action.

In testimony whereof we afiix our signatures. i v

- HARRY S. LEE.

'azone' which has a predeterminedfcross section forthe purpose of screenlng the material.

What we claim 1 S l I 1; In rotating ball mills or'the like, a screen plurality of openings therethrough which are relatively long and narrow, each of said-openings being 3 converging walls comprising a plate having a bounded by oppositely which converge inwardly from the ends of opening, said opening having a metered portion connecting the oppositely converging walls, said plurality of openings beingidisstan'tially parallel a the mill as a center, whereby the balls in the i mill move across the openings in a direction substantially paralleling the length of the openings to minimize the peening action on the edgesof theopening. i V

'- 2. In rotating ball mills or the'like, a screen having a plurality of long and narrow, each of said openings being bounded by oppositely converging wall's which converge inwardly from he ends of lengthwise dimensions subn archavlng theaxls'of of'said openings hav- 85 WEBSTER nnorxkaisnnf sic 9 

